In recent years, it has been known that articles, such as light transmissive films having a fine concavo-convex structure with a cycle of the wavelength or less of visible light on the surface thereof, exhibit an antireflection effect, the Lotus effect and the like. Particularly, it is known that a concavo-convex structure called a moth-eye structure can serve as effective means for antireflection due to the refractive index continuously increasing from the refractive index of air to the refractive index of a material of the articles.
As a method for manufacturing a light transmissive film having a fine concavo-convex structure on the surface thereof, for example, a method having the following steps (i) to (iii) (nanoimprint) is known.
(i) A step of sandwiching an active energy ray-curable composition between a mold having an inversion structure of a fine concavo-convex structure on the surface and a base material film which serves as a main body of a light transmissive film.
(ii) A step of irradiating the active energy ray-curing composition with active energy rays, such as ultraviolet rays, curing the active energy ray-curable composition so as to form a cured resin layer having a fine concavo-convex structure, and obtaining a light transmissive film.
(iii) A step of separating the light transmissive film and the mold.
Meanwhile, in the mold, generally, since the cycle of fine pores is on the nanometer order, and the aspect ratio of the fine pores is also relatively large, the contact interface between the mold and the active energy ray-curable composition significantly increases. Therefore, there is a problem in that it is difficult to release the mold from the cured resin layer. Therefore, in particular, the above step (iii) is considered to be important from the viewpoint of productivity.
As a method for improving the release property between the mold and the cured resin layer, the following method has been proposed.
(1) A method in which the fine concavo-convex structure-formed surface of a mold is treated using a release agent (external release agent) (Patent Literature 1).
(2) A method in which a solid-form photo-curable transfer layer made of a photo-curable resin composition including a phosphate ester-based compound as an internal release agent (Patent Literature 2).